In recent years, sintered silicon carbide materials, as well as sintered silicon nitride materials, have been used as high temperature, high strength materials, e.g., for gas turbines, high temperature furnaces or rocket nozzles. Further, utilizing their low friction characteristics, they have been used as a low friction members such as sealing rings, etc. Furthermore, utilizing their electric characteristics, they have been used as heat elements such as an ignitor which is represented by, for example, a glow type electric ignitor or a glow plug.
A glow type electric ignitor is a device which in response to an electric input generates a thermal output within a temperature range suitable, for example, for the ignition of a fuel, such as natural or artificial gas or the like. Such ignitor has utility in ranges, ovens, dryers, furnaces and similar appliances and devices.
However, in order to effectively utilize such ceramics which are brittle materials in such uses, it is necessary to bond them with metals or with another ceramic parts.
The processes for forming metallized surfaces used hitherto for alumina ceramics does not provide satisfactory results in bonding strength, air tightness at sealing areas and electric conduction when it is applied to sintered silicon carbide materials.
In light of the above described circumstances, the present invention provides a metallized surface composition for metallizing the surface of a sintered silicon carbide material and a process for producing the same.
Sintered silicon carbide materials have good wetting ability for silicon, as can be understood from the fact that reaction sintered silicon carbide materials are produced by impregnating the same with silicon between silicon carbide particles and carbon particles. However, sintered silicon carbide materials have a simple silicon surface can not be used, because simple silicon surface has so poor adhesive strength to silicon carbide that the resulting simple silicon layer peels off with impact, even if it wets silicon carbide, and it also has no adhesive strength to Ni plating or soldering materials.